How rare is the tentacled lagoon worm? A conservation physiology approach

Estuarine environments are amongst the most diverse and productive marine ecosystems, however the animals living within them must contend with some of the most extreme environmental conditions, particularly with respect to fluctuating salinities over the tidal cycle. Polychaete worms are one such group which is widely distributed in estuarine habitats where changes in salinity necessitate physiological adjustments to maintain internal homeostasis. Whilst polychaetes are widely considered to be osmoconformers, this is based on studies of a very limited number of common species, and significant gaps in our understanding remain, despite this group being of fundamental ecological importance. These gaps are not only of relevance to studies of osmoregulatory capacity, but mean that we have a very limited grasp of the factors shaping polychaete distribution, despite them being major components of estuarine food webs. At the same time the effects of climate change are projected to have major repercussions for estuarine systems and therefore it is vital that we also quantify the potential effects of future stressors on the biology of these important species.

The ‘tentacled lagoon worm’ Alkmaria romijni Horst 1919 (Annelida, Ampharetidae) is ≤ 5 mm long surface deposit feeding tube building polychaete that inhabits muddy sediments in brackish water habitats (Fig. 1). It is ecologically important in the estuarine food chain, and in sediment stabilisation and oxygenation. Although recorded from Sweden to Morocco, it has a discontinuous distribution. In the UK, it has been considered to be a specialist and characteristic ecologically important lagoonal species, leading to its protection, and it is listed as a ‘species feature of conservation importance’ within UK marine conservation zones. However, around the UK coast A. romijni has been recorded from 27 sites, in salinities ranging from 5-48 ppt in both estuaries and lagoons, whilst in other areas of its range it has been described both from non-tidal brackish waters and as a ‘genuine brackish water animal’. Alkmaria romijni is a protandrous hermaphrodite which initially broods its larvae in its tube. After ~12 days these larvae then become free-living on the surface of the sediment, developing their own tube at ~20 days, making them an ideal laboratory model. However, despite its ecological importance and its protected status, the physico-chemical factors underpinning the distribution of A. romijni remain uncharacterised.

Despite being an ‘uncharismatic’ species recent work has confirmed that when informed about the ecological role/ecosystem services that this species provides the public are prepared to support the conservation of species such as A. romijni. This project will provide further evidence to inform its conservation and that of the Erme estuary (Fig. 2). This project will also complement work already being undertaken by the Ecophysiology and Development Research Group in SoBMS at UoP to understand the effect of extremes of salinity and temperature on coastal species.

This PhD project will explore and quantify the factors which determine the habitat preferences, ecological requirements, and distribution of the tentacled lagoon worm, A. romijni using a conservation physiology approach. The project will have three main objectives:

Students will be embedded in the Ecophysiology and Development Research Group and receive training in a broad range of ecophysiological approaches (whole animal physiology, biochemical and developmental biology analyses), together with cutting edge omics and molecular ecology techniques, alongside ecological field survey methods. Training will also be given in transferrable scientific skills including data analysis (e.g. of ecophysiological, (R) and molecular ecology (MEGA, DnaSP, Arlequin, R) datasets) and in scientific writing and presentations.